1. Field of the Invention
The present invention relates to a patch preparation having a support containing an inorganic oxide layer and a pressure-sensitive adhesive layer containing a drug.
2. Description of the Related Art
In recent years, a transdermal absorption-type patch preparation that delivers a drug into a living organism by being applied to a skin surface has been developed. The patch preparation has been attracting attention because of such an excellent advantage as described below. The patch preparation can maintain a plasma drug concentration within an effective therapeutic range for a long time period, can be easily applied, or can avoid a first liver pass effect. With regard to such patch preparation, the realization of a preparation that exerts a sufficient drug effect with a small preparation area or in a short patch time is expected to lead to an improvement in quality of life (QOL) of a patient. The realization of such preparation requires an improvement in drug releasability. The drug releasability of a patch preparation can be generally improved by such means as the increase of a drug concentration in the patch preparation or the addition of an absorption enhancer. However, such means may adversely affect the physical properties and drug stability of the patch preparation (or its drug-containing pressure-sensitive adhesive layer), and concerns are rising that it takes a considerable time period and a considerable cost to establish means for solving the problem.
A technology for improving the drug releasability by means of an occlusive dressing technique (ODT) effect has been proposed to avoid such problem as described above. Such technology basically involves making the patch preparation lowly moisture-permeable. For example, Japanese Patent Application Laid-open No. Hei 4-244019 describes that drug releasability is improved with the ODT effect caused by covering a support with a covering material that can be easily released and is lowly moisture-permeable. The technology described in Japanese Patent Application Laid-open No. Hei 4-244019 realizes the low moisture permeability not by making the support lowly moisture-permeable but by using the lowly moisture-permeable covering material. In addition, U.S. Patent Application Publication No. 2006-0078604 describes a technology involving causing the ODT effect with a lowly moisture-permeable support to improve drug releasability. The literature describes a single layer or laminate of a specific polymer film as the lowly moisture-permeable support (for example, paragraphs 0369 to 0382).
However, a patch preparation described in Japanese Patent Application Laid-open No. Hei 4-244019 is not such that the support itself is responsible for the low moisture permeability. Although a patch preparation described in U.S. Patent Application Publication No. 2006-0078604 is such that the support itself is responsible for the low moisture permeability, the anchoring property of its drug-containing pressure-sensitive adhesive layer has room for improvement. Insufficient anchoring property of the drug-containing pressure-sensitive adhesive layer may adversely affect its patch property, and hence a situation in which an expected effect is not obtained may occur. Therefore, a patch preparation that can sufficiently utilize the ODT effect and is excellent in drug releasability, and whose drug-containing pressure-sensitive adhesive layer is excellent in anchoring property has been desired.